【摘要】 以西安地铁明挖区间隧道穿过地裂缝带为研究背景,通过几何比1∶5的大比例尺地裂缝与地铁隧道模型试验,研究了地裂缝活动引起地铁隧道地层应力与位移变化规律。试验结果表明:地裂缝活动在上盘地层中产生负的附加应力,出现应力降低区,而在下盘产生正的附加应力,出现应力增强区,且距离地裂缝越远附加应力越小。随上盘沉降量的增大,上盘隧道顶部地层应力增加,两侧逐渐减小,而下盘隧道顶部地层应力逐渐减小接近于零,两侧地层应力则逐渐增大。地层位移和地表沉降变形随地裂缝位错量增加而增大,横向呈现上、下盘相反的变化规律,同时上盘地表出现与地裂缝近似垂直的纵向拉张裂缝,影响范围约为2倍隧道宽度,下盘地表出现与地裂缝大致平行的横向拉张裂缝,影响宽度约为2.5倍隧道宽度。研究结果可为地裂缝环境下地铁隧道沿线城市规划与地裂缝灾害防治提供参考。更多还原

【Abstract】 Based on the Xi’an metro open-cut tunnel passing through the active ground fissures,through three-dimensional model tests with geometric proportion of 1:5,the change laws of stratum stress and displacement near the metro tunnel induced by the active ground fissures are studied. The test results show that under the action of active ground fissures,the negative additional stress is created in the stratum of the hanging wall of the ground fissures and there appears a stress reduced area; but in the foot-wall the positive additional stress is created in stratum and there appears a stress enhanced area; and the additional stress reduces with the increasing distance from the ground fissures. With the increasing settlement of the hanging wall,the soil pressure of top tunnel increases and bilateral soil pressure decreases gradually in the hanging wall,but it is just reverse in the foot-wall. Displacement of stratum and settlement deformation of the ground surface increase with settlement of the hanging wall,and displacement and deformation laws in the hanging wall are inverse from the foot-wall in horizontal direction of tunnel. Meanwhile,in the hanging wall there appear surface tensile cracks approximately perpendicular with the active ground fissures and in the foot-wall surface tensile cracks are approximately parallel to the active ground fissures. The conclusions can be used as the reference for the urban layout along metro under the environment of active ground fissures,and for the prevention and treatment of ground fissure hazards.更多还原